Conventionally, as a saddle type vehicle having a water cooled engine, there is known, as disclosed, for example, in Patent Document 1, one equipped with a thermostat 94 (FIG. 5) provided in a cooling water path of a water cooled engine 16, and a check valve 82 (FIG. 6) provided in a secondary air path supplying secondary air to an exhaust path of the water cooled engine 16.